Computer Aided Design (CAD) revolutionized 2D drafting, with the majority of practices throwing their drawing boards away and benefitting from adopting a digital workflow. However, design technology and best practice are always being redefined and enhanced to find competitive advantage.
Today firms realize a ‘2D’ solution only provides documentation. The adoption of 3D is becoming standard practice, as it brings designs to life, provides the benefits of automatic documentation, analysis, and visualization prior to manufacture. But as we all know, what is actually produced is rarely the same as the original CAD model. So how can we capture and import the real world physical form back into a CAD system? Technologies such as laser scanning are now offering new design possibilities.
Quality inspection and checking fabricated parts against a master CAD model have assisted in the QA functions in industries such as semiconductor, Automotive and Aerospace and enable engineers to instantly visualize deviations from the nominal. Engineers can also be used to scan tools and fixtures to identify wear. While much of this is carried out using fix-bed coordinate measuring machines (CMM), laser scanners offer bigger range and speed and are now getting more portable and their price is dropping. The main drawbacks are dealing with reflective surfaces (lasers are light after all) and documenting recessed features or enclosed components, but here X-ray machines are making great strides to capture geometry inside and out.
Firms that maintain and create new factory layouts are also benefitting from 3D CAD and the use of laser scanning. For new layouts there are a number of applications that can model assembly lines to check for clashes, piping, power and efficiency. For existing designs there is a growing trend to laser scan facilities ‘as is’ for facilities management or remodelling.
As an example, to design the manufacturing system for a powertrain design Ford allows 48 months lead-time. By adopting an upfront virtual manufacturing approach, the assembly lines can be designed simultaneously with the product, offering obvious time saving benefits.
Ford now uses laser scanners to capture each of its manufacturing plants in great detail, so it can run manufacturing simulation in the actual plant. While Ford has many 2D drawings of its factories, the laser scans give rapid access to the as-built nature of the factory content to project teams around the world. This can then be used to more accurately make design changes by combining modelled CAD data as it moves through the assembly line with the point-cloud of the factory giving a virtual experience together with clash detection prior to installation.
Laser scanners usually capture images along with point clouds, enabling ‘fly throughs’ of facilities in 3D. This can save a huge amount of modelling time, allowing only the important elements to get modelled in-context. This could be to see existing equipment or to help plan changes. How could you use laser scans to improve your facilities?
Concept and Rework
Traditional hand drawn sketches or CAD sketch profiles are the start point of a design. Industrial design may follow function or, with today’s cultured consumers, something more aesthetic or fitting may be the order of the day. With most CAD software now able to read in native point clouds, it’s possible to start a design with a shape found in the real world. For parts that have no drawings and need repairing, scans can be imported, repaired and new components manufactured. In fact, the Space Shuttle had a laser scanner on its robotic arm to scan the tiles for damage after reaching orbit. A 3D model was sent back where anomalies could be analyzed and damage volumes correctly identified for simulated repair.
While lasers measure millions of 3D points by hitting a surface, it’s also possible to reconstruct a 3D form with multiple photographic views. Autodesk’s 123D Catch is a great example of this. Take a number of photographs around an object you want modeled and send them all up to the cloud. Here powerful servers apply complex mathematical techniques to derive the camera’s original position and builds an equivalent faceted, bit mapped, mesh model of the surfaces in the images. The beauty of this solution is that it would work with a simple camera, one of which is in every phone. While currently not as accurate as laser scanners the technology is very promising and scales up from bolts to capture buildings and landscapes.
Advances in technology mean that design information can be created, captured from reality, edited, mixed and matched, inspected, clashed and even fabricated with today’s CAD systems.
Laser scanners and point cloud data are starting to become commonly used in all areas of design, either providing original inspiration, ‘as is’ models for rework, quality information or assisting in the fabrication and management of factories.